Analyses Of Wheat Yellow Mosaic Virus(WYMV)Complete Genome Sequence And Protein Interaction And Sub-cellular Localization Of WYMV Protein

Wheat yellow mosaic disease (WYMD) is an important disease in wheat in the middle and lower streams of the Yellow, and Yangzi Rivers. This disease leads to serious yield loss of about1.5×109kg in China, and threatens the safety of grain production.Wheat yellow mosaic virus (WYMV), genus Bymovirus (family Potyviridae), is the major pathogen causing WYMD in China. WYMV, transmitted by plasmodiphorids vector, Polymyxa graminis L., is a bipartite virus and contains two genomic RNAs.In this study, we reported the complete genomic sequences of two WYMV isolates from Tai’an and Linyi. The RNA1and RNA2of both isolates were7635nt and3651nt, respectively, excluding the3’-terminal poly (A) tail. In the phylogenetic trees calculated with complete RNA1and RNA2ORF sequences, all the WYMV isolates were clustered to two groups (Ⅰ and Ⅱ), and group I was further clustered to two subgroups (Ia and Ib). The RNA1ORF of both Tai’an and Linyi isolates were clustered to group II. The RNA2ORF of Tai’an isolate was clustered to group Ib, but that of Linyi isolate was clustered to group II.We presented the interaction map between WYMV proteins by yeast two hybrid systems (YTHS). The result shows that CP, P3N-PIPO,7K, CI, VPg, NIa-Pro, PI can self-interact,7K can inteact with NIb, and VPg can interact with14K. Both P3-AD and P3NPIPO-AD interact with NIb-BD;7K-AD interacts with P1-BD,P2-BD; CI-AD interacts with7K-BD, NIa-BD;14K-AD interacts with7K-BD, P3NPEPO-BD, NIa-BD, P2-BD; VPg-AD interacts with NIb-BD; NIb-AD interacts with14K-BD; CP-AD interacts with P3NPIPO-BD, CI-BD, VPg-BD, NIa-BD, P2-BD; P1-AD interacts with P2-BD, P2-AD interacts with NIb-BD. We found that many interactions were unidirectionally in YTHS. Further evidence of YTHS and bimolecular fluorescence complementation (BiFC) assays showed that the N-terminal (1～86amino acids) of P1was responsible for the self-interaction of PI.Finally, we fused the proteins of WYMV with GFP and analyzed the sub-cellular localization of the proteins in Nicotiana benthamiana epidermal cells.The result showed that NIb localized exclusively to nuclei. P2localized the cell plasma and cytoplasmic skeleton. Not only PI but also CP could develop vesicles in cell plasma. P3and CI localized the cell plasma and the cell membranes. NIa-Pro and7K localized the cell plasma. Each of the14K and P3N-PIPO localized to the cell periphery and associated with membranes, VPg localized the nucleolus.